Stabilization of mineral hydrocarbon products



Patented Dec. 24, 1935 STABILIZATION F MINERAL HYDRO- CARBON PRODUCTS Frederick Baxter Downing, Oarneys Point, N. J.,

and Herbert Warren Walker, Wilmington, Del., assignors to E. I. du Pont de Nemours & Com- P y, ware Wilmington, DeL. a corporation of Dela- No Drawing. Continuation of application Serial No. 484,703, September 26, 1930. This application January 20 1933, Serial No. 652,775

13 Claims.

This invention relates to improvement in means for the stabilization of mineral hydrocarbon products. More particularly it relates to the utilization of organic compounds as addition products for substances of the class named. The tendency of liquid hydrocarbons to discolor and to form gum, sludge and resinous substances is at present the bte noire of all persons connected with their production, distribution and use.

Gasolines, for example, as produced by the modern cracking processes are extremely complicated mixtures comprising many constituents. The character of these constituents and the relative proportions of each depend upon the source of the crude petroleum and the particular cracking process employed. Ordinarily substantialpercentages of unsaturated aliphatic and aro- 2 matic hydrocarbons are present. In certain instances these percentages are intentionally increased by the addition of unsaturated compounds to gasolines. Such additions may also be made to gasolines not containing unsaturated hydrocarbons. Regardless of how produced, gasolines containing these unsaturated compounds form, in the presence of air, a series of products some of which are resinous or gummy. These gums or resins form sticky substances 30 which deposit on the walls and bottom of the container in which the gasolines are stored and in some instances discolor the gasoline. Certain portions of the gums formed may be soluble in the gasoline but they are also objectionable be- 35 cause of the consequent introduction of nonvolatile components into the gasoline. Exposure to sunlight causes discoloration which in some instances is accompanied by appreciable gum- Slmilar problems or disadvantages are encountered with motor benzol which is the name applied to a material similar to gasoline in physical properties but which consists largely of aromatic or unsaturated hydrocarbon compounds.

these disadvantages or to treat the. crude prod- In the past it has been necessary to tolerate use of hydrocarbon motor fuels'which are free from gum and to prevent gum formation in more highly cracked gasolines which would otherwise develop excessive amounts of gum and thereby be rendered unfit for ordinary use. 5 Still further objects are to make it possible to use as an internal combustion fuel liquid hydrocarbons such as gasoline that contain larger amounts of unsaturated compounds than commercially used at present, to produce a. product of this sort at lower cost and to produce one which in certain instances possesses improved anti-knock properties. Other objects will appear hereinafter.

These objects may be accomplished according to the present invention wherein a member or members of the group comprising dihydroxynaphthalenes are added in small quantities to mineral hydrocarbons. The invention will be more readily understood from a consideration of the example which follows in which the parts are given by weight.

One of the tests used for evaluating. the effectiveness of this class of compounds as stabilizers or gum inhibitors is the accelerated oxygen test. In this test twenty-five (25) cc. of motor. fuel, cracked gasoline, motor benzol, or the like, treated with 0.001 to 1% of the stabilizing agent are heated at 100 C. in an atmosphere of oxygen for 3 to 6 hours. The gum formed is measured by evaporating the hydrocarbon after the oxygen testfrom a porcelain. dish in the steam oven. The extent of gum formation during the accelerated oxygen test is a measure of the stability and gumming tendency of the fuel during the long time storage.

Example 1 Cracked gasoline treated with 0.02% 1:5-dihydroxy-naphthalene gave 16 mg. gum per 25 cc. in the accelerated oxygen gum test run for five and one-half hours. The gum formed in the same gasoline, but not stabilized, under the same conditions was 120 mg. per 25 cc. I

It is not desired to limit the invention to the concentration of the stabilizing agent given in the above example. Use may be made of higher or lower concentrations of any member of the group of compounds disclosed above and as a .result thereof greater or less inhibition of gum formation and prevention of discoloration secured depending upon the specific agent used, the solubility of the agent, the. concentration of the agent, the nature of the material treated and the conditions under which the treatment and subsequent storage take place. The preferred actual concentration of the stabilizing agent may vary between the limits of 0.001 to 1%. It will be apparent, however, that this range is not given as limiting since lesser or greater amounts may be usedin specific instances within the scope of the invention. In most instances no marked advantage is gained by using more than the maximum amount set out above. In any event the range given appears to be suflicient for the grades of gasoline and oils of similar characteristics now on the market.

The invention is not limited to the specific stabilizing compound set out in the above example. In general, the dihydroxy naphthalenes have been found suitable for use in accordance with this invention. Some of these compounds which we have fond to be particularly satisfactory are the following:

(i) 1.2-dihydroxy-naphthalene (2) 1.4-dihydroxy-naphthslene (3) l.7-dlhydroxy-naphthalene i OH w (4) 2.3-dihydroxy-naphthalene It is to be understood that other isomers and homologue's in the class mentioned abovemay be used. In certain cases, it has been found advantageous to use two or more of the specific compounds covered by this invention. It will be appreciated that the example outlined above and the specific compounds mentioned are given merely for the purpose of illustrating and not for limiting the invention.

Obviously this invention is of great importance in freeing internal combustion engines from the annoyance and improper functioning due to the deposition-of gum in the fuel containers or fuel systems.

As many apparently widely difierent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims.

This application is a true continuation of our copending application for "Mineral oil stabilization filed September 26, 1930, Serial No. 484,703. 5

1. A motor fuel comprising cracked hydrocarbon spirits normally tending to form gum and having a dihydroxy naphthalene incorporated therein in an amount suflicient to inhibit the formation of gum.

2. Motor benzol normally tending to form gum and having a dihydroxy naphthalene incorporated therein in an amount suflicient to inhibit the formation of gum.

3. A motor fuel comprising cracked gasoline normally tending to form gum and having a dihydroxy naphthalene incorporated therein in an amount suificient to inhibit the formation of 4. A motor fuel comprising cracked gasoline normally-tending to form gum and having 1:5'-dihydroxy naphthalene incorporated therein in an amount suflicient to inhibit the formation of gum.

5. The method of inhibiting the formation of 25 gum by an unsaturated gasoline normally tending to form gum which comprises adding to the mineral oil a dihydroxy naphthalene in an amount from 0.001 to 1% to inhibit the formation of gum. i 30 6. The method ofinhibiting the formation of gum by motor benzol normally tending to form gum which comprises adding to the motor fuel a dihydroxy naphthalene in an amount sufficient to inhibit the formation of gum. I

7. The method of inhibiting the formation of gum by a cracked gasoline normally tending to form gum which comprises adding to the gasoline. 1:5-dihydroxy naphthalene in an amount sufficient to inhibit the formation of gum.

8. A cracked gasoline normally tending to develop gummy substances upon storage and containing a dihydroxy naphthalene compound in quantity sufliclent to retard such gum formation.

9. A cracked gasoline normally tending to de- 4 velop gummy substances upon storage and containing 1:2-dihydroxy-naphthalene in quantity suflicient ,to retard such gum formation.

10. A cracked gasoline normally tending to develop gummy substances upon storage and con-- taining 1:4-dihydroxy-naphthalene in quantity sufficient to retard such gum formation.

11. Motor benzol normally tending to deteriorate and form gum on. storage and containing 1:2-dihydroxy naphthalene in quantity suflicient 

